Multi-field Inflation with a Random Potential

Abstract

Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the inflaton to undergo a Brownian motion with a drift in the D-dimensional field space. To quantify such an effect, we employ a stochastic approach to evaluate the two-point and three-point functions of primordial perturbations. We find that in the weakly random scenario the resulting power spectrum resembles that of the single field slow-roll case, with up to 2% more red tilt. The strongly random scenario, leads to rich phenomenologies, such as primordial fluctuations in the power spectrum on all angular scales. Such features may already be hiding in the error bars of observed CMB TT (as well as TE and EE) power spectrum and can be detected or falsified with more data coming in the future. The tensor power spectrum itself is free of fluctuations and the tensor to scalar ratio is enhanced. In addition a large negative running of the power spectral index is possible. Non-Gaussianity is generically suppressed by the growth of adiabatic perturbations on super-horizon scales, but can possibly be enhanced by resonant effects or arise from the entropic perturbations during the onset of (p)reheating. The formalism developed in this paper can be applied to a wide class of multi-field inflation models including, e.g. the N-flation scenario.

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References in corpus (56)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• de Sitter Vacua in String Theory
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Axions In String Theory
• Generating the curvature perturbation without an inflaton
• A General Analytic Formula for the Spectral Index of the Density Perturbations produced during Inflation
• A new approach to the evolution of cosmological perturbations on large scales
• A general proof of the conservation of the curvature perturbation
• The primordial density perturbation in the curvaton scenario
• Adiabatic and entropy perturbations from inflation
• The inflationary prediction for primordial non-gaussianity
• N-flation
• Assisted inflation
• Non-Gaussianity of the primordial perturbation in the curvaton model
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectra
• Inflationary perturbations from a potential with a step
• High resolution CMB power spectrum from the complete ACBAR data set
• Primordial non-gaussianities from multiple-field inflation
• Generation and Characterization of Large Non-Gaussianities in Single Field Inflation
• Scalar perturbations during multiple-field slow-roll inflation
• Primordial perturbations and non-Gaussianities in DBI and general multi-field inflation
• Perturbations in generalized multi-field inflation
• Enhancement of superhorizon scale inflationary curvature perturbations
• Generating the curvature perturbation at the end of inflation
• Multiple inflation
• Generalized Assisted Inflation
• Random Matrices and the Spectrum of N-flation
• Primordial fluctuations and non-Gaussianities in multi-field DBI inflation
• Inflation and WMAP three year data: Features have a Future!
• Multi-brid inflation and non-Gaussianity
• Inflationary perturbations near horizon crossing
• Axion Inflation in Type II String Theory
• Multiple inflation and the WMAP 'glitches'
• Duality Cascade in Brane Inflation
• Spinflation
• Non-gaussianity from the bispectrum in general multiple field inflation
• Multiple inflation and the WMAP 'glitches' II. Data analysis and cosmological parameter extraction
• Primordial Non-Gaussianities of General Multiple Field Inflation
• Multifield DBI Inflation and Non-Gaussianities
• Cosmology From Random Multifield Potentials
• Chain Inflation in the Landscape: "Bubble Bubble Toil and Trouble"
• Curvature perturbation from symmetry breaking the end of inflation
• Large Volume Axionic Swiss-Cheese Inflation
• Rapid Tunneling and Percolation in the Landscape
• Graceful exit from a stringy landscape via MSSM inflation
• Dynamical renormalization group methods in theory of eternal inflation
• Staggered Multi-Field Inflation
• Multi-Field Inflation on the Landscape
• "Finite" Non-Gaussianities and Tensor-Scalar Ratio in Large Volume Swiss-Cheese Compactifications
• Simplified Chain Inflation
• Disorder on the landscape
• Chain inflation revisited
• Inflation without Inflaton(s)
• Tachyon Mediated Non-Gaussianity
• Chain inflation and the imprint of fundamental physics in the CMBR
• Vacuum Sampling in the Landscape during Inflation

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• Features of heavy physics in the CMB power spectrum
• Inflation, Cosmic Perturbations and Non-Gaussianities
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• A geometric description of the non-Gaussianity generated at the end of multi-field inflation
• Turning intractable counting into sampling: computing the configurational entropy of three-dimensional jammed packings
• Charting an Inflationary Landscape with Random Matrix Theory
• Exploring a string-like landscape
• From Wires to Cosmology
• Untangling features in the primordial spectra
• On Gaussian Random Supergravity
• Cosmic inflation in a landscape of heavy-fields
• Non-Gaussianities of Single Field Inflation with Non-minimal Coupling
• Disorder in the Early Universe
• A Meandering Inflaton
• Consistency relations for sharp features in the primordial spectra
• Manyfield Inflation in Random Potentials
• On the Suppression of Parametric Resonance and the Viability of Tachyonic Preheating after Multi-Field Inflation
• Probability of Slowroll Inflation in the Multiverse
• Multifield Stochastic Particle Production: Beyond a Maximum Entropy Ansatz
• Initial conditions and sampling for multifield inflation
• Curvature Perturbations From Stochastic Particle Production During Inflation
• Modular Inflation at Higher Level $N$
• Stochastic Particle Production in a de Sitter Background
• Coupling structure of multi-field primordial perturbations
• Stochastic collapse
• Particle Production during Inflation in Light of PLANCK
• On mass spectra of primordial black holes
• The Distribution of Vacua in Random Landscape Potentials
• Entropy Perturbations in N-flation
• Curvaton: Perturbations and reheating
• Inflation in a Gaussian Random Landscape